GEAR UP LNDG IN SMT TWIN AFTER PARACHUTE JUMPING ACTIVITY IS TERMINATED.

Narrative

AFTER DROPPING A LOAD OF SKYDIVERS FROM 13500 FT MSL I USUALLY LOWER THE GEAR FOR THE EXTRA DRAG FOR THE DSCNT. DURING THE DSCNT I WENT FURTHER N OF THE FIELD THAN USUAL. AT ABOUT 5000 MSL I RETRACTED THE GEAR SO I WOULD NOT HAVE TO ADD ANY PWR TO MAKE IT BACK TO THE FIELD. THERE WAS NO TFC IN THE AREA SO I RPTED ON L BASE FOR THE RWY. I WENT THROUGH MY USUAL CHKLIST INCLUDING GEAR DOWN. AGAIN ON FINAL I WENT THROUGH LIST INCLUDING GEAR DOWN. COMING IN ON FINAL A BUNCH OF THE SKYDIVERS CAME RUNNING OUT TOWARDS THE RWY. I STARTED LOOKING FOR OTHER TFC OR TRYING TO FIGURE WHAT THEY WANTED ME TO GAR FOR. I SAW NO OTHER TFC OR HEARD NONE ON THE RADIO SO I PROCEEDED THE APCH. NO ONE WAS STANDING ON THE RWY SO I FIGURED THEY WERE MESSING AROUND. ABOUT THE TIME I THOUGHT THE GEAR WAS GOING TO TOUCH I HEARD THE NOISE OF THE PROPS TOUCHING. I GAVE IT FULL PWR AND LIFTED THE NOSE. I COULD TELL BY THE FEEL THAT I WAS NOT GOING TO BE ABLE TO CLB. THE PROPS WEREN'T HITTING BUT I WAS NOT GETTING ANY CLB RATE GOING. WITH ONLY 3000 FT OF RWY I PULLED THE THROTTLES TO IDLE AND LANDED FLAT AS POSSIBLE. WHEN THE ACFT CAME TO A STOP I LOOKED AT THE GEAR SELECTOR AND IT WAS IN THE DOWN POS; BUT THE RED LIGHT WAS ON. I DON'T KNOW IN MY OWN MIND IF IT WAS RED THE WHOLE TIME OR JUST AFTER I CAME TO A STOP. I AM GOING TO DO A RETRACT TEST ON JACKS FOR THE FAA. THEN I SHOULD HAVE A BETTER IDEA OF WHY THE GEAR DID NOT COME DOWN.